<%!
/**
 * This stream filter converts a stream of bytes to their Base64 encoding.
 *
 * Base64 encoding encodes 3 bytes into 4 characters. |11111122|22223333|33444444| Each set
 * of 6 bits is encoded according to the toBase64 map. If the number of input bytes is not a
 * multiple of 3, then the last group of 4 characters is padded with one or two = signs. Each
 * output line is at most 76 characters.
 */
class Base64OutputStream extends FilterOutputStream
{
   /**
    * Constructs the stream filter
    * @param out the stream to filter
    */
   public Base64OutputStream(OutputStream out)
   {
      super(out);
   }

   public void write(int c) throws IOException
   {
      inbuf[i] = c;
      i++;
      if (i == 3)
      {
         super.write(toBase64[(inbuf[0] & 0xFC) >> 2]);
         super.write(toBase64[((inbuf[0] & 0x03) << 4) | ((inbuf[1] & 0xF0) >> 4)]);
         super.write(toBase64[((inbuf[1] & 0x0F) << 2) | ((inbuf[2] & 0xC0) >> 6)]);
         super.write(toBase64[inbuf[2] & 0x3F]);
         col += 4;
         i = 0;
         if (col >= 76)
         {
            super.write('\n');
            col = 0;
         }
      }
   }

   public void flush() throws IOException
   {
      if (i == 1)
      {
         super.write(toBase64[(inbuf[0] & 0xFC) >> 2]);
         super.write(toBase64[(inbuf[0] & 0x03) << 4]);
         super.write('=');
         super.write('=');
      }
      else if (i == 2)
      {
         super.write(toBase64[(inbuf[0] & 0xFC) >> 2]);
         super.write(toBase64[((inbuf[0] & 0x03) << 4) | ((inbuf[1] & 0xF0) >> 4)]);
         super.write(toBase64[(inbuf[1] & 0x0F) << 2]);
         super.write('=');
      }
      /*
      if (col > 0)
      {
         super.write('\n');
         col = 0;
      }
      */
   }

   private char[] toBase64 = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K',
         'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b',
         'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's',
         't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
         '+', '/' };

   private int col = 0;
   private int i = 0;
   private int[] inbuf = new int[3];
}

/**
 * Computes the Base64 encoding of a string
 * @param s a string
 * @return the Base 64 encoding of s
 */
public String base64Encode(String s)
{
   ByteArrayOutputStream bOut = new ByteArrayOutputStream();
   Base64OutputStream b6out = new Base64OutputStream(bOut);
   try
   {
      b6out.write(s.getBytes());
      b6out.flush();
   }
   catch (IOException e)
   {
   }
   return bOut.toString();
}
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